Traffic light control



1935- E. R. ANDERSON TRAFFIC LIGHT CONTROL 2 Sheets-Sheet 1 Filed Dec. 4, 1929 Green drm an Oct. 1, 1935. E. R. ANDERSON TRAFFIC LIGHT CONTROL 2 Sheets-Sheet 2 Filed Dec. 4, 1929 gnuewhw Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE 15 Claims.

This invention relates to street and highway intersection traflic controlling signals and has particular reference to trafiic signals of the automatic electrically operated type wherein use is 5 made of colored lights intermittently energized for regulating the movements of trafllc through street and highway intersections.

It is an outstanding object of the invention to provide an electrically operated visual type of 10 highway signal wherein each face of the signal is provided with but two lamps or lenses, usually red and green, instead of employing the customary three lenses to indicate red, yellow and green. Heretofore the yellow signal has been 15 employed between the energized periods of the red and green signals in order to produce a period of warning permitting of the clearing of the intersection prior to the change in the movement of the direction of traffic. In accordance with 20 the present invention the use 01' this yellow or amber signal is dispensed with in order that the signal structure as a whole may be more simplifled in operation and economically constructed but without loss of the functions heretofore se- 25 cured through the use of the yellow or caution signal.

The present invention therefore embodies a circuit control so constructed and operated that at or about the time of termination of the ener- 30 gizing of the green or go signal an intermittent flashing or energizing of either the green or red signal is produced, whereby oncoming drivers will be notified of the impending change in the signal from the green or go period to the red or 35 stop period, the intermittent flashing of one or the other of said signals providing the necessary warning in order to provide for the stopping of oncoming vehicles and to permit of the clearing of the street intersection.

For a further understanding of the invention reference is to be had to the following description and the accompanying drawings wherein:

Figure 1 is a diagrammatic view illustrating the controlling circuit employed in governing the energizing of the incandescent lamps employed in the signal. In this figure the stop or red lamp controlling east and west tramc is shown 'as energized and the green signal employed in 50 controlling north and south tramc is energized.

Figure 2 is a similar view of the controlling circuit showing the flash switch closed for intermittently energizing the red signal governing north and south traflic, the green signal for gov- 55 eming north and south traflic energized and the red signal for governing east and west tramc energized.

Figure 3 is another diagrammatic view illustrating a third circuit governing position wherein the red signal for north and south tramc and 5- E1116 egreen signal for east and west traflic are ener- Figure 4 is a similar view showing the circuit arrangement wherein the green signal for east and west t'raflic and the red signal for north and south trafllc are energized and wherein the red signal for east and west trafllc is being'intermittently energized to indicate the termination of the go or clear period provided by the green signal or the east and west traillc, and

Figure 5 is a perspective view of the circuit controller illustrating diagrammatically the as sociated lamps governed thereby.

Referring more particularly to the drawings, the numeral I indicates the current input line which leads from any suitable source of energy, for the signal, while the numeral 2 indicates the return line. The line I extends to a circuit controller A which is preferably mounted within the casing 3 of the trailic signal which is adapted to be positioned in any suitable manner in connection with a street intersection in order that it may be conveniently viewed byapproaching vehicle drivers.

The controller A consists of a rotatably jourq naled shaft 4 which is constantly rotated at a predetermined speed of rotation by, for example, an electrical motor 5, shown in Figure 1, which is shunted across the lines i and 2. The shaft 4 has keyed or otherwise secured thereto a plurality of switch cams, the numeral 6 indicating the cam employed in controlling the energizing of the green or go signals, the cam I indicating the cam employed in controlling the red or stop signals, and the cam 8 being employed in controlling the intermittent energizing of one oi the previous signals, preferably the red signal, at approximately the period of termination 01' the green signal. The cams 6 and I are practically identical in construction and each includes a pcripheral area 9 of maximum diameter and a peripheral area ill of reduced diameter, the peripheral surfaces 9 and I0 being joined by abrupt shoulders I l. The flash cam 8 substantially duplicates the construction of the cams 6 and I with the exception that its surface 9 terminates in a plurality of serrations or teeth l2 by which rapid opening and closing movements are imparted to an associated switch to intermittently energize a complemental circuit.

Stationarilyarranged within the casing 3 and suitably suported therein is a fixed shelf it formed from insulating material. To this. shelf there is suitably secured the fixed inner ends of a plurality of resilient and metallic contact bars 14. These bars have their outer or free ends provided with insulating pads ii in order to alternately space the bars it from a plurality of contact brackets it which are rigidly carried by the resilient outer endsof the bars ll. The vertical legs of the brackets It engage with the peripheral surfaces 9, l0, II and I! of the cams 6, 1 and 8, in order that the rotation of the cams may govern the operating positions of the bars l4.

The bars I! are positioned between upper and lower contact strips II of insulating material which extend at right angles to the bars M and are stationarily supported in any suitable-manner in the casing 3. The strips l1, opposite the bars I 4, are provided with oppositely disposed metallic contacts I8 which are adapted to be engaged with the bars M by the operation and positions of the cams 6, I and 8.

Electrical energy enters the controller by way of the line I and then by means of the branch wires i9 is transmitted to each of the contact bars l4 and thence through said bars to the stationary contacts l8. Wires 20 extend from the contacts l8 to the incandescent lamps 2| which are used in providing the visual signals secured by the operation of the apparatus, and conductors 22 lead from the return sides of the lamps 2| to the return line 2 of the system. The respective pairs of binding posts are designated by the reference characters a, b, c, d, e and f, as clearly shown in Figure 5 of the drawings.

As shown in Figure 5, the trafllc signal comprising the present invention embodies on each signalling side but two lamps one for the purpose of producing a red or "stop signal and the other for producing a green or go signal. 2i are surrounded by reflectors 23 and the open sides of these reflectors are closed by means of colored glass lenses 24.

In Fig. 5, one side of the electrical supply I, through I9, is connected to contact carrying cam followers l4, over cams 6, 1 and 8. Stationary contact 0 is connected to north and south stop, d is connected to east and west stop, e is connected to east and west go and f is connected to north and south go signal indications. The other side of the source of electrical supply (2) is common to all signal indications. Thus, if only two cams 6 and 1 actuating their respective cam followers l4, between stationary contacts e and f and c and d were involved and the high and low portions of said cams were respectively positioned in alignment, upon rotation of said cams 6 and I, they would effect a simultaneous energization of the east and west go and the north and south stop signal indications while on the high portions of the cams and make an abrupt change from the above condition to that of energizing the north and south go and the east and west stop signal indications upon cam followers l4, riding the low portion of cams 6 and 1.

Obviously, if the stationary contact 0 is connected by jumper to contact a, the north and south stop signal indications may be energized through either or both of these contacts, similarly, if in the same manner contacts b and d are interconnected the east and west stop signal indications may be energized through either or both of these contacts, therefore, if a third cam, 8, having The lamps a series of serrations or notches II, at the beginning and the end of its high portion is so positioned with respect to cams t and I, that 'a given number of notches l2, are effective in advance of the high portion 9, of the latter cams, it is obvi- 5 ous that while cam followers it over I and I are adjacent to the low portion of these cams that cam follower it, over cam 8, upon reaching notches l2, will rise and fall and thus produce an intermittent energization of the north and 10 south stop signals through contact a, simultaneous with steady energization of the north and south go signals through contact I. and the east and west stop signals through contact d. Upon cam followers ll, reaching the high portion of 15 their respective cams, contacts a and 0 function in unison to steadily energize north and south stop signals and contact e, to energize east and west go signals, therefore, if the notches l2,'at the end of the high portion of cam 8 are in E0 advance of and terminate at the beginning of the low portions of cams 6 and I, it necessarily follows that upon cam follower ll, over cam l, reaching lowermost positions in said notches, it will intermittently energize east and west stop signals 25 through contact b during the steady energization of the east and west go signal and the north and south stop signals. Thus in this particular arrangement an intermittent flashing effect is imparted to the stop signals prior to the termination 30" of the period of activity of the go signals in any given direction, while an abrupt change from stop to go signal condition is effective in any given direction. The flashing effect of the stop signal combined with the steady energization of the 35 go signal serves as a notification to moving traffic of an impending change in directional tramc movement and provides a period for such traflic to come under control preparatoryto stopping,

while the abrupt change from stop to go signal 40" condition precludes the tendency to pre-start as is the general practice where a caution or other signal indication is displayed following the stop signal, and before the go signal is effective.

In operation, the shaft 4 is constantly rotated 45 east and west is energized and likewise the red 55 signal for governing north and south traflic is energized. In this position, however, the green signal on the east and west trafilc is about to be extinguished to permit of the energizing of the red signal. it is customary to deenergize the green signal and energize a yellow or amber signal which remains energized for a short interval when it is extinguished and the red signal is energized. In accordance with the present invention, however, immediately prior to the extinguishing of the green signal the teeth I2 of the cam 8 cooperate with the associated bar I l to intermittently energize the red signal disposed imme- 70 diately above the green signal which is about to be extinguished. This produces an intermittent flashing of the red signal which notifies oncoming traffic drivers of the impending change of the traflic controlling signals and the conse- 7g In ordinary apparatus of this kind quent flow of trafllc at the street intersection protected by the signals.

The terms continuously, "predetermined and active as used are meant to define the steady display of the signal lights for their entire time. The term effective is that portion of such time in which one signal light alone is displayed to indicate distinctly stop" or go traffic, depending on which particular signal is displayed.

By this method of operation and construction I reduce the number of lamps required in a traffic signal assembly with corresponding simplicity of construction, economy in manufacture and with accompanying decreased repairs and replacements of parts, without loss of function of the caution signal. It is, of course, within the scope of the invention to intermittently flash the green or red lamp at the end of any signal period to provide the caution warning, and I, therefore, do not limit myself to the precise structural features and method of operation hereinbefore set forth, but reserve the right to employ all such modifications and equivalents thereof which fall within the scope of the following claims.

What is claimed is:

1. The method of regulating the operation of highway intersection traffic signals by means of stop and go visual electrical light signals, which includes energizing the go signal for a predetermined period, intermittently flashing the stop signal immediately prior to the termination of the period of activity of the go signal and subsequently continuously energizing the stop signal for its active period at the termination of the active period of the go signal.

2. The method of regulating the operation of highway intersection traffic signals by means of stop and go visual electrical light signals, which includes energizing the go signal for a predetermined period, intermittently flashing the stop signal immediately prior to the termination of the period of activity of the go signal and subsequently continuously energizing the stop signal for its active period at the termination of the active period of the go signal and then again continuously energizing the go signal for its active period immediately upon the termination of the period of activity of the stop signal.

3. The method of regulating the operation of highway intersection traflic signals by means of stop and go visual electrical light signals, which includes energizing the go signal for a predetermined period, intermittently flashing the stop signal immediately prior to the termination of the period of activity of the go signal, and subsequntly continuously energizing the stop signal for its active period substantially at the termination of the active period of the go signal.

4. The method of regulating the opera-tion of highway intersection trafiic signals by means of stop and go visual electrical light signals, which includes energizing the go signal for a predetermined period, intermittently flashing the stop signal immediately prior to the termination of the period of activity of the go signal, and subsequently continuously energizing the stop signal for its active period substantially at the termination of the active period of the go signal, and then again continuously energizing the go signal for its active period immediately upon the termination of the period of activity of the stop signal.

5. The method of regulating the operation of highway intersection traiflc signals to indicate period, then indicating caution by the continu- 6 I ous illumination of one of the signal lights simultaneously with the flashing of the other signal light for an effective period, and then indicating stop by the continuous illumination of the second signal light for an effective period. 10

6. The method of regulating the operation of highway intersection traflic signals by means of stop and go visual electrical light signals, which includes energizing the go signal for its effective period, then immediately thereafter lntermittently flashing the stop signal, then subsequently continuously energizing the last mentioned signal for its effective period, then de:nergizing the last mentioned continuously energized signal and reenergizing the flrst mentioned signal for an effective period.

7. The method of regulating the operation of highway intersection tramc signals by means of stop and go visual electrical light signals, which includes energizing the go signal for its effective period, then immediately thereafter intermittently flashing the stop signal; then subsequently continuously energizing the last mentioned signal for its effective period, then deenergizing the last mentioned continuously energized signal, and successively repeating the aforesaid cycle of signal energization.

8. In a two light signal system for controlling traffic at highway intersections, stop and go visual electrical light signals, means for energizing the go signal for its effective period, means for immediately thereafter intermittently energizing the stop signal to create an intermittent flashing thereof, and additional means for then continuously energizing the last mentioned signal for an effective period, and means for continuously repeating the operation of the aforesaid means.

9. In a system for controlling trafie at highway intersections, stop and go visual electrical light signals, means for energizing one of the signals for a predetermined period, means for intermittently energizing the other signal to create an intermittent flashing thereof prior to the termination of said period of the first mentioned signal, and additional means for continuously ener- 5o gizing the last mentioned signal for a predetermined period at the termination of the flashing activity thereof.

10. The method of regulating the operation of highway intersection trafiic signals by means of stop and go visual electrical light signals, which includes; energizing the go signal for an active period, intermittently flashing the stop signal immedlately prior to the termination of the period of activity of the go signal, and subsequently 0 continuously energizing the stop signal for its active period substantially at the termination of the active period of the go signal, and successively repeating the aforesaid cycle of signal energization. 5

11. In a system for controlling traffic at highway intersections, stop and go visual electrical light signals approachable by traffic on each of a plurality of different lanes, means for energizing the go signal for an active period, means for intermittently flashing the stop signal immediately prior to the termination of the period of activity of the go signal, means for subsequently continuously energizing the stop signal for an effective period at the termination of the active period of the go signal, means for again continu ously energizing the go signal for an effective period immediately upon the termination of the said period of the stop signal.

12. The method of regulating the operation of highway intersection traffic signals to indicate go, caution or warning of change in directional traflic movement, and stop, by means of visual electrical light signals having two contrasting color indications, one indicating go and the other stop, approachable by trafilc on each of the plurality of different lanes, which includes; energizing the first of the said signals for an active period, intermittently energizing the other signal to create a flashing thereof prior to the termination of the active period of the first :mentioned signal and subsequently continuously energizing the second mentioned signal for an effective period substantially at the termination of the flashing activity thereof, then deenergizing the last mentioned continuously energized signal, and again continuously energizing the first mentioned signal.

13. In a system for controlling trafiic approaching highway intersections on each of a plurality of different lanes, visual electrical light signals having two contrasting color indications, one indicating g0 and the other stop, means for energizing the first of the said signals for an active period, means for intermittently energizing the other signal to create a flashing thereof prior to the termination of the active period of the first mentioned signal, means for subsequently continuously energizing the second mentioned signal for an effective period substantially at the termination of the flashing activity thereof, means for deenergizing the last mentioned continuously energized signal, and means for reenergizing the first mentioned signal.

14. The method of regulating the operation of highway intersection traflic signals to provide; traflic movement, caution or warning of directional change in traflic movement, and traiiic stop periods, by means of visual electrical light signals having two distinct color indications, normally indicating stop and go, approachable by traffic on each of a plurality of different lanes,

which includes; continuously and simultaneously energizing the north and south go and the east 5 and west stop signals for an active period, intermittently energizing the north and south stop signals to create an intermittent flashing thereof prior to the termination of and concurrently with the period of activity of the north and south 10' go signals, then deenergizing the active signals and simultaneously with such deenergization, energizing the north and south stop and east and west go signals for an active period. intermittently energizing the east and west stop signals is to create an intermittent flashing thereof prior to the termination of and concurrently with the active period of the east and west go signals, then deenergizing the active signals and successively repeating the aforesaid cycle of signal it energization. 15. In a system for controlling trafilc at highway intersections, visual electrical light signals having two distinct color indications, normally indicating stop and go, approachable by trafilc $6 on each of a plurality of different lanes, means for continuously and simultaneously energizing the north and south go and the east and west stop signals for an effective period, means for intermittently energizing the north and south stop 80 signals to create an intermittent flashing thereof after the termination of the effective period of the north and south g0 signals, means for deenergizing the displayed signals, means for thereafter energizing the north and south stop and cut and west II go signals for an effective period, means for intermittently energizing the east and west stop signals to create an intermittent flashing thereof after the termination of the effective period of the east and west go signals, means for deenergizing the 40 displayed signals, means for successively repeating the aforesaid cycle of signal energlzation.

EUGENE R. ANDERSON. 

